Who watches the watchers circling overhead in U.S. skies? A congressional hearing on the possible risks of domestic drones lamented the absence of the U.S. Department of Homeland Security and its failure to step up to take responsibility.

Homeland Security officials told Congress that their duties don't cover the domestic use of drones in the U.S., according to U.S. Rep. Michael McCaul, a Republican from Texas and chairman of the subcommittee hearing of the U.S. House Committee on Homeland Security. But McCaul worried that the agency was "reverting back to a pre-9/11 mindset" with a "lack of imagination in identifying threats."

"It should not take a 9/11 style attack by a terrorist organization such as Hezbollah or a lone wolf- inspired event to cause DHS (Department of Homeland Security) to develop guidance addressing the security implications of domestic drones," McCaul said in his opening remarks on July 19.

Today's usage of drones in the U.S. remains limited to the law enforcement, border patrol, firefighting and weather or scientific research. But the Federal Aviation Administration plans to allow non-government drones to fly nationwide by 2015, starting with the selection of six test sites this year.

Taking control

News headlines have highlighted several drone-related threats and security issues. A man who plotted to attack the U.S. Capitol and Pentagon with remote-controlled aircraft agreed to plead guilty last week. Hacked drones pose a different danger, as U.S. researchers showed how they could take control of a remote-controlled helicopter during a GPS "spoofing" test in June.

Non-recreational drones over 18 pounds should require "spoof-resistant" GPS or other navigation systems to foil hackers, said Todd Humphreys, engineer at the University of Texas at Austin. He testified during the congressional hearing as one of the researchers who carried out the June hacking demonstration.

To counter hacking threats, Humphreys recommended that the Department of Homeland Security fund creation of an authentication signature for civilian GPS signals.

The Government Accountability Office previously suggested that the Transportation Security Administration look at the security risks of future civilian drones. Nobody has followed up on that recommendation, said Gerald L. Dillingham, director of physical infrastructure issues for the GAO.

Protecting privacy

A different but equally important issue comes from ensuring people's privacy in the midst of domestic drone swarms. But no federal agency currently has specific responsibility over such drone-related privacy matters, Dillingham said.

Drones present a new threat to the privacy of U.S. citizens because they can provide cheaper, more extensive surveillance over longer periods, said Amie Stepanovich, association litigation counsel for the Electronic Privacy Information Center, during her testimony about privacy risks. [Laser Could Keep Military Drone Flying Forever]

"Drones could be deployed to monitor individuals in a way that was not possible previously," Stepanovich said.

Stepanovich advised the Department of Homeland Security to make more information publicly available about its own large drone fleet. She also recommended that Congress pass new laws regulating domestic drone use.

Uncertain future

Even William McDaniel, chief deputy of the Montgomery County Sheriff's Office in Conroe, Texas, suggested that the Department of Homeland Security step up to coordinate federal oversight of drone activities and local law enforcement's use of drones.

"We are disappointed DHS declined to testify today," McCaul said. "This is simply another example of how DHS leadership is failing to get ahead of the curve on an issue which directly impacts the security of the United States."